Problem: Solve for $p$ : $26 + p = 30$
Subtract $26$ from both sides: $ \begin{eqnarray} \\ 26 + p &=& 30 \\ \\ {-26} && {-26} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{26 + p} &\hphantom{=}& \hphantom{30} \\ p &=& 30 {- 26} \\ \end{eqnarray} $ Simplify. $ p = 4$